In a machine successively making plastic bags, it is required to mount a heat seal bar on a heater unit so that plastic films can be heat sealed with each other by the heat seal bar, as disclosed in Japanese Laid-Open Patent Publication No. 2001-310398. In general, a bolt is used to mount the heat seal bar on the heater unit. However, the heat seal bar is formed of aluminum and therefore soft. In this connection, the heat seal bar has to be reinforced by an insert. The insert is cylindrical, including outer and inner threads, as disclosed in Japanese Laid-Open Patent Publication No. 2002-130255. In addition, a hole is formed in the heat seal bar so that the insert can be received in the hole and engaged therewith threadedly. The bolt is received in the insert and engaged therewith threadedly, mounting the heat seal bar on the heater unit.
In this case, it is required to remove the heat seal bar and mount it again for adjustment of position when changing the size of plastic bag. In addition, it is required to remove the heat seal bar and mount it again for exchange of heat seal bar when changing a width with which the plastic films are heat sealed and when changing a shape with which the plastic films are heat sealed. In this connection, it should be understood that in general, the machine includes more than 4 heat seal bars. In addition, a plurality of bolts are used for each of the heat seal bars. It is therefore troublesome to manipulate the bolts by tool when removing each of the heat seal bars and mounting it again, taking time and labor. In particular, the heat seal bar is kept being heated at a high temperature during removing it, making the work difficult when taking time for removing the heat seal bar.
It is therefore an object of the invention to provide an apparatus for mounting a heat seal bar on a heater unit in a machine successively making plastic bags, which can mount and remove the heat seal bar without difficulty.